The above invention relates to a quick-connection coupling of flat configuration with arrangements for avoiding hydraulic fluid escaping during a joining or separating operation.
The prior art has disclosed the use of quick-connection couplings of so-called flat configuration. These couplings comprise a tubular component, also referred to as receiving component, which is connected to flexible conduits for channeling a pressurized hydraulic fluid.
It is possible to connect to the tubular component, which is a constituent part of the quick-connection coupling, a second component, which is essentially cylindrical.
The cylindrical component can be connected, via flexible conduits, to a piece of equipment, e.g. a tractor, some other agricultural machine or a construction machine, e.g. an excavator.
The abovementioned machines are usually equipped with different auxiliary arrangements. These auxiliary arrangements are fitted on the machine or removed therefrom, depending on the requirements at any one time.
Quick-connection couplings of flat configuration are used for these operations. These couplings are connected to conduits which accommodate highly pressurized hydraulic fluid. The couplings used allow rapid connection or release, the hydraulic fluid in the conduits being pressurized.
By virtue of the known quick-connection coupling of flat configuration, it is possible for the components of the coupling to be joined without any mechanical difficulties, and this connecting operation can also be carried out when the hydraulic fluid in the flexible conduits is pressurized.
For this purpose, in the known quick-connection couplings, there is provided, in the tubular or in the projecting component of the coupling, a single-piece inner, tubular sliding part which, according to the prior art, is designed as a single-piece component.
In the case of a quick-connection coupling which is of such a construction, hydrostatic shearing forces which are of the same magnitude as one another but act in opposite directions, and occur both in the interior of the tubular component and in the interior of the projecting components, make it possible for the single-piece sliding part, which is arranged in the interior of the tubular coupling part, to be easily displaced.
This displacement operation is carried out during a coupling movement, even if there are considerable pressures prevailing in the conduits.
The quick-connection coupling of this type known from the prior art has the disadvantage that, during the movement of the sliding part, which is provided as a single-piece component in the interior of the tubular coupling element, a critical situation occurs beneath the different components, between the displacement body and the annular seal arranged in the interior of the tubular component, and this results in the elimination of the hydrostatic equilibrium between the different components of the quick-connection coupling and the establishment of a shearing force which extends in the axial direction and leads to an extraordinarily quick displacement movement of the movable component and to the sealing ring arranged in the interior of the tubular component being suddenly released.
In the case of the known quick-connection coupling, this fact results in the undesirable escape of hydraulic fluid during each joining or separating operation.
Furthermore, damage to the sensitive sealing ring, which inevitably results in hydraulic fluid being lost, is unavoidable, particularly if the operation of joining the quick-connection coupling takes place relatively frequently.
It is an object of the above invention to avoid the disadvantages of the prior art and to propose a novel quick-connection coupling in the case of which there is no uncontrolled and sudden, premature displacement movement of the inner displacement element, and the situation where the annular seal arranged in the interior of the tubular component is influenced by a pressurized hydraulic fluid and is damaged during repeated joining or separating operations of the components of the quick-connection coupling is thus avoided.
According to the invention, these objects are achieved by means of a quick-connection coupling of flat configuration in that the tubular component has an inner displacement element which is designed in two parts, and these parts are arranged concentrically with one another and can be displaced in relation to one another.
It is particularly advantageous for the displacement element to comprise two parts, i.e. a first tubular component, of which the front part has a guide and displacement surface for a sealing ring which is arranged in the interior of the projecting component which is to be connected, it being the case that the guide and sliding surfaces terminate at a stop step against which a spring means butts, and the first tubular component is accommodated in a displaceable manner by the front element of a second tubular component, and this second tubular component has a step which can be influenced by the end of the first tubular component, the free end of the second tubular component having a collar which interacts with an annular protrusion of a union sleeve, which is arranged in a stationary manner.
A further advantage is that an annular seal is provided between the inner surface of the first tubular component and the outer surface of the second tubular component.
A sealing means is advantageously provided between the front part of an inner receiving shaft and the first tubular component.
Furthermore, it has proven advantageous to provide a centrally arranged receiving shaft, of the tubular component, which is provided, on its front side, with a circumferentially extending step against which the front end of the first tubular component, which is a constituent part of the displaceable, two-part arrangement, butts.